JPH08239461A - Aliphatic polyester copolymer and its production - Google Patents

Abstract

PURPOSE: To produce an aliphatic polyester having biodegradability and a practicably high molecular weight and excellent in heat stability, tensile strength, etc., by polycondensing an aliphatic or alicyclic diol with an aliphatic dicarboxylic acid in the presence of an aliphatic hydroxycarboxylic acid. CONSTITUTION: In a process for producing an aliphatic polyester having a number-average molecular weight of 10,000-200,000 by polycondensing an aliphatic or alicyclic diol with an aliphatic dicarboxylic acid or its derivative in the presence of a catalyst, the polycondensation is performed in the presence of 0.04-60mol, per 100mol of the aliphatic dicarboxylic acid or its derivative, of an aliphatic hydroxycarboxylic acid as a comonomer. This polyester is one comprising 0.02-30mol% aliphatic hydroxycarboxylic acid units represented by formula I, 35-49.99mol% aliphatic or alicyclic diol units represented by formula II and 35-49.99mol% aliphatic or alicyclic diol units represented by formula III and having a number-average molecular weight of 10,000-200,000. In the formulas, R<1> is a bivalent aliphatic hydrocarbon group; R<2> is a bivalent aliphatic hydrocarbon group or a bivalent alicyclic hydrocarbon group; and R<3> is a direct bond or a bivalent aliphatic hydrocarbon group.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a high molecular weight aliphatic polyester copolymer which can be molded into a desired molded article by a general-purpose plastic molding method such as an injection molding method, a hollow molding method and an extrusion molding method, and its production. It is about the method. More specifically, it relates to an aliphatic polyester having biodegradability, a high molecular weight sufficient for practical use, and excellent thermal stability and tensile strength.

[0002]

2. Description of the Related Art Conventionally, polyesters used for molding films, fibers and other molded articles have been high molecular weight polyesters having a number average molecular weight of 10,000 or more. This high molecular weight polyester was limited to an aromatic polyester prepared from terephthalic acid and ethylene glycol or 1,4-butanediol, and the aliphatic polyester was extremely small. The reason why the aliphatic polyester has not been put to practical use is that (1) the melting point of the aliphatic polyester is relatively low, and (2) the number average molecular weight of the aliphatic polyester is 15,000 in the polycondensation reaction which is generally known. Other than the above, it is easily decomposed by heat, and a practically sufficient strength could not be obtained with a molecular weight of about 10,000.

As proposed in JP-A-4-189822 and JP-A-5-287043, the number average molecular weight is 5,000 or more, preferably 10,
A polyester diol having a hydroxyl group of 000 or more and a terminal group being substantially a hydroxyl group is added with an isocyanate as a coupling agent in a molten state at a temperature higher than its melting point to obtain an aliphatic polyester containing a high molecular weight urethane bond. Although obtained, the aliphatic polyester containing a high-molecular-weight urethane bond has problems such as coloring and generation of microgel depending on the conditions when molded by a general-purpose plastic molding method.

Further, as proposed in JP-A-5-310898, a glycol component and an aliphatic dicarboxylic acid component are esterified, and the produced polyester diol is present in the presence of a catalyst in a temperature range of 180 to 230 ° C. , And a deglycolization reaction under a high vacuum of 0.005 to 0.1 mmHg give a number average molecular weight of 25,000.
Although a high molecular weight aliphatic polyester having a hydroxyl group at the terminal group is synthesized at 0 to 70,000, it is industrially difficult to obtain such a high vacuum state.

Further, Japanese Patent Laid-Open No. 5-43665 discloses that
An aliphatic oxycarboxylic acid such as lactic acid or glycolic acid is heated in the presence of a germanium compound under an inert gas stream or under reduced pressure to effect dehydration polycondensation to give a reduced viscosity of 0.67 to 0.8.
A method of making the aliphatic polyester of 9 is disclosed. Films and molded articles obtained from this aliphatic polyester also do not have practically sufficient mechanical strength.

[0006]

An object of the present invention is to provide an aliphatic polyester copolymer which is biodegradable, has a practically sufficient high molecular weight, and is excellent in thermal stability and tensile strength. To provide.

[0007]

Means for Solving the Problems The inventors of the present invention have diligently studied to solve the above problems and provide an aliphatic polyester having biodegradability and at the same time being sufficiently practical. In the presence of a catalyst such as a compound, by using an aliphatic or alicyclic diol and an aliphatic dicarboxylic acid or a derivative thereof as main components, and copolymerizing a specific amount of an aliphatic oxycarboxylic acid such as lactic acid or glycolic acid,
It was found that the polymerization rate was remarkably increased, and as a result, a high molecular weight aliphatic polyester copolymer having a number average molecular weight of 10,000 or more could be obtained very easily without using a chain extender. Reached Further, this high molecular weight aliphatic polyester copolymer has a relatively high melting point and practically sufficient strength, and the introduction of an oxycarboxylic acid component reduces the crystallinity of the resulting polyester, resulting in flexibility. Is to have. Furthermore, the high molecular weight aliphatic polyester of the present invention exhibits excellent biodegradability.

In order to solve the above problems, in the invention described in claim 1, 0.02 to 30 mol% of an aliphatic oxycarboxylic acid unit represented by the following formula (I) and represented by the following formula (II) Aliphatic or cycloaliphatic diol units 35-49.9
An aliphatic polyester comprising 9 mol% and 35 to 49.99 mol% of an aliphatic dicarboxylic acid unit represented by the following formula (III), and having a number average molecular weight of 10,000 to 200,000. The means to make a copolymer is taken. ^{(I) -O-R 1 -CO-} ( wherein, R ¹ represents a divalent aliphatic hydrocarbon group) in ^{(II) -O-R 2 -O-} ( wherein, R ² is a divalent aliphatic hydrocarbon group or a divalent alicyclic hydrocarbon group) (III) in -OC-R ³ -CO- (wherein, R ³ is a direct bond or a divalent aliphatic hydrocarbon group)

Further, in the invention described in claim 5, in the presence of a catalyst, an aliphatic or alicyclic diol and an aliphatic dicarboxylic acid or a derivative thereof are reacted by a polycondensation reaction to give a number average molecular weight of 10,000 to 20. In the production of various aliphatic polyesters, the amount of the aliphatic oxycarboxylic acid is 0.04 per 100 mol of the aliphatic carboxylic acid or its derivative.
Means of copolymerizing -60 mol is taken.

The present invention will be described in more detail below. The aliphatic oxycarboxylic acid corresponding to the aliphatic oxycarboxylic acid unit of the above formula (I) in the present invention is particularly limited as long as it is an aliphatic compound having one hydroxyl group and carboxylic acid group in the molecule. rather, the formula, HO-R ¹ -
COOH, (wherein R ¹ is represented by a divalent aliphatic hydrocarbon group. Further, formula (V) corresponding to the aliphatic oxycarboxylic acid unit of the above formula (IV),

[0011]

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An aliphatic oxycarboxylic acid represented by the formula (1 is 0 or 1 to 10, preferably 0 or an integer of 1 to 5) is particularly preferable in that the effect of improving the polymerization reactivity is recognized.

Specific examples of the aliphatic oxycarboxylic acid include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid,
Examples thereof include 2-hydroxycaproic acid, 2-hydroxy3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, or a mixture thereof. When these have optical isomers, D
It may be a body, an L body, or a racemate, and may be in the form of a solid, a liquid, or an aqueous solution. Of these, preferred is lactic acid or glycolic acid,
Particularly preferred is lactic acid or glycolic acid, which has a particularly remarkable increase in the polymerization rate during use and is easily available.
The form is preferably a 30 to 95% aqueous solution because it is easily available. These aliphatic oxycarboxylic acids can be used alone or as a mixture of two or more kinds.

The diol corresponding to the aliphatic or alicyclic diol unit of the above formula (II) is not particularly limited, but refers to a compound represented by the formula: HO-R ² -OH. Here, in the formula, R ² is a divalent aliphatic hydrocarbon group or 2
It is a diol having a valent alicyclic hydrocarbon group. As a preferable divalent aliphatic hydrocarbon group, R ² is — (CH
₂ ) An aliphatic hydrocarbon group represented by _n- (n is an integer of 2 to 10) is exemplified. It is particularly preferable that n is 2
To 6 aliphatic hydrocarbon groups. As a preferred divalent alicyclic hydrocarbon group, R ^{2 in} the above formula is an alicyclic hydrocarbon group having 3 to 10 carbon atoms, and among them, particularly preferred is 4 to
6 is a divalent alicyclic hydrocarbon group of 6.

Specific examples of the aliphatic or alicyclic diol represented by the above formula (II) include ethylene glycol, trimethylene glycol, 1,3-propanediol,
1,4-butanediol, 1,5-pentanediol,
Preference is given to 1,6-hexanediol, 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol. From the viewpoint of the physical properties of the obtained copolymer, 1,4-butanediol is particularly preferable. These may be used alone or as a mixture of two or more.

Examples of the aliphatic dicarboxylic acid corresponding to the aliphatic dicarboxylic acid unit of the above formula (III) or its derivative include HOOC-R ³ --COOH, where R ³ is a direct bond or a divalent fatty acid. represented by family hydrocarbon group, _{preferably, - (CH 2) m -} , where m is 0 or 1 to 10
Of the above, preferably 0 or an integer of 1 to 6), or a lower alcohol ester thereof having 1 to 4 carbon atoms, such as dimethyl ester, or an acid anhydride thereof.

Specific examples thereof include oxalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedioic acid, and their lower alcohol esters, succinic anhydride, adipic anhydride, and the like. From the viewpoint of physical properties of the obtained copolymer, succinic acid, adipic acid, sebacic acid or their anhydrides, and their lower alcohol esters are preferable, and especially succinic acid, succinic anhydride,
Alternatively, mixtures of these are preferred. These are alone 2
A mixture of more than one species can be used.

The production of the high molecular weight aliphatic polyester of the present invention comprising the aliphatic or alicyclic diol, the aliphatic dicarboxylic acid or its derivative and a small amount of the aliphatic oxycarboxylic acid can be carried out by a known technique. The polymerization reaction at the time of producing this polyester can set the suitable conditions conventionally adopted, and is not particularly limited.

The amount of the aliphatic or alicyclic diol used is
The amount is substantially equimolar to 100 mol of the aliphatic dicarboxylic acid or its derivative, but in general, 1 to 20 mol% is used in excess because distilling occurs during esterification. The amount of the aliphatic oxycarboxylic acid to be added is such that if the amount of the aliphatic oxycarboxylic acid is too small, the effect of addition does not appear, and if it is too large, the crystallinity is lost, which is not preferable in molding, and heat resistance,
Inadequate mechanical properties. The amount of the aliphatic oxycarboxylic acid is 100% by weight of the aliphatic dicarboxylic acid or its derivative.
The amount is preferably 0.04 to 60 mol, more preferably 1.0 to 40 mol, and particularly preferably 2 to 20 mol.

The timing and method of adding the aliphatic oxycarboxylic acid are not particularly limited as long as they are before the polycondensation reaction.
Examples include (1) a method of adding the catalyst in a state of being dissolved in an aliphatic oxycarboxylic acid solution in advance, and (2) a method of adding the catalyst at the same time as the catalyst is added when the raw materials are charged. The aliphatic polyester copolymer of the present invention is preferably produced by using the above raw materials in the presence of a polymerization catalyst. As a catalyst,
Germanium compounds are preferred. The germanium compound is not particularly limited, and examples thereof include organic germanium compounds such as germanium oxide and tetraalkoxy germanium, and inorganic germanium compounds such as germanium chloride. Because of price and availability
Germanium oxide, tetraethoxy germanium, tetrabutoxy germanium and the like are preferable, and particularly germanium oxide is preferable. In addition, other catalysts may be used in combination as long as the object of the present invention is not impaired.

The amount of the catalyst used is 0.001 to 3% by weight, preferably 0.005% by weight, based on the amount of the monomer used.
~ 1.5% by weight. The timing of adding the catalyst is not particularly limited as long as it is before polycondensation, but may be added at the time of charging the raw materials or at the start of depressurization. A method of adding the catalyst at the same time as the aliphatic oxycarboxylic acid such as lactic acid and glycolic acid at the time of charging the raw materials or by dissolving the catalyst in an aqueous solution of the aliphatic oxycarboxylic acid is preferable. Particularly, the storage stability of the catalyst becomes good. In view of this, a method of dissolving the catalyst in an aliphatic oxycarboxylic acid aqueous solution and adding the catalyst is preferable.

The conditions such as temperature, time and pressure for producing the aliphatic polyester copolymer are such that the temperature is 150 to 26.
The temperature is preferably 0 ° C, preferably 180 to 230 ° C, and the polymerization time is preferably 2 hours or longer, more preferably 4 to 15 hours. The degree of reduced pressure is preferably 10 mmHg or less, more preferably 2 mmHg or less. The composition ratio of the aliphatic polyester copolymer of the present invention must be such that the molar ratio of the aliphatic or alicyclic diol unit of the formula (II) and the aliphatic dicarboxylic acid unit of the formula (III) is substantially equal. Is. The aliphatic or alicyclic diol unit and the aliphatic dicarboxylic acid unit are each in the range of 35 to 49.99 mol%, preferably 40 to 49.75 mol%, more preferably 45.
It is preferable to select in the range of ˜49.5 mol%. Also, (I)
The aliphatic oxycarboxylic acid unit of the formula is preferably selected in the range of 0.02 to 30 mol%. 3 aliphatic oxycarboxylic acids
If it exceeds 0 mol%, the crystallinity will be lost, which is not preferable for molding, and if it is less than 0.02 mol%, the effect of addition will not appear.
The above range is preferably 0.5 to 20 mol%, and more preferably 1.0 to 10 mol%.

The number average molecular weight of the aliphatic polyester copolymer of the present invention is 10,000 to 200,000, preferably 30,000 to 2
It is 0,000. Further, other copolymerization components can be introduced into the aliphatic polyester copolymer of the present invention as long as the effects of the present invention are not impaired. Other copolymerization components include aromatic oxycarboxylic acids such as hydroxybenzoic acid, aromatic diols such as bisphenol A, aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid, or polyvalent compounds such as trimethylolpropane and glycerin. Examples thereof include alcohols, polyvalent carboxylic acids or their anhydrides, and polyvalent oxycarboxylic acids such as malic acid.

As described above, the present invention has an aliphatic or alicyclic diol unit, an aliphatic carboxylic acid unit, and an aliphatic oxycarboxylic acid unit in a specific ratio and has a number average molecular weight of 10,000 or more. , And more preferably 30,000 or more, based on the fact that the high molecular weight aliphatic polyester copolymer has practically sufficient strength and melting point. in particular,
By using an aliphatic oxycarboxylic acid such as lactic acid,
It was possible to achieve a high molecular weight extremely easily.

The high molecular weight aliphatic polyester copolymer according to the present invention can be formed into a film by a general-purpose plastic molding method such as an injection molding method, a hollow molding method and an extrusion molding method.
It can be used for molded products such as laminated film, sheet, board, stretched sheet, monofilament, multifilament, non-woven fabric, flat yarn, staple, crimped fiber, streak tape, split yarn, composite fiber, blow bottle, foam, etc. . At that time, a crystal nucleating agent, an antioxidant,
Lubricants, colorants, release agents, fillers, other polymers, etc.
It can be added if necessary.

Further, the high molecular weight aliphatic polyester copolymer according to the present invention is biodegradable and has the property of being completely decomposed by bacteria in the soil within 2 to 12 months, which is environmentally friendly. It is a very useful polymer. Therefore, from now on, applications such as shopping bags, garbage bags, agricultural films, cosmetic containers, detergent containers, bleach containers, fishing lines, fishing nets, ropes, binding materials, surgical threads, sanitary cover stock materials, cold storage boxes, cushion materials, etc. Is expected to be used.

[0027]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded. The characteristic values in the following examples were measured by the following methods. (1) Polymer composition: The composition was calculated from the area ratio of the obtained spectrum by ¹ H-NMR method. (2) Number average molecular weight (Mn); measured by GPC method. Dissolve the sample in chloroform and use Tosoh GP
It was measured by polystyrene conversion using C HLC-8020. As the column, PLgel-10μ-MIX was used.

(3) Thermal properties; DSC method (heating rate 16
Melting point was determined by (measured under nitrogen at C / min). (4) Tensile properties: From the polyesters obtained in Examples and Comparative Examples, a thickness of 0.30 to 0.
Create a 37mm film and use this film to JIS K
No. 2 dumbbell was prepared in accordance with 7127. The breaking elongation and breaking strength of this dumbbell were measured according to JIS K7127. (5) Biodegradability test: A film having a thickness of 0.30 to 0.37 mm was prepared from the obtained polyester by a desktop hot pressing method, and this was cut into 2 cm x 2 cm to prepare a test piece. The test piece was immersed in soil for 3 months, and the biodegradability was visually confirmed.

[Example 1] In a reaction vessel having a capacity of 100 ml equipped with a stirrer, a nitrogen inlet tube, a heating device, a thermometer, and an auxiliary agent addition port, 35.4 g of succinic acid and 28 of 1,4-butanediol were added. 0.4 g and 2.9 g of a 90% lactic acid aqueous solution in which 1% by weight of germanium oxide was dissolved in advance were charged.
Nitrogen gas was introduced into the contents of the container with stirring, the temperature was raised to 180 ° C. in a nitrogen gas atmosphere, and the reaction was carried out at this temperature for 45 minutes, and then under a reduced pressure of 20 mmHg for 1.75 hours. Subsequently, the temperature was set to 220 ° C. and polymerization was carried out for 4 hours under a reduced pressure of 0.5 mmHg. ¹ H of the obtained polyester
-The polymer composition by NMR is lactic acid unit 4.6 mol%, 1,4-butanediol unit 47.7 mol%, succinic acid unit 47.7 mol%, Mn is 58,900,
The melting point was 108 ° C. A film was prepared from this polymer by hot pressing on a table, and a tough film was obtained. Further, as a result of the biodegradability test, many worm-eaten holes were observed on the film after 3 months, and biodegradability was confirmed.

Example 2 A reaction vessel having a capacity of 150 ml equipped with a stirrer, a nitrogen inlet tube, a heating device, a thermometer and an auxiliary agent addition port was charged with 59.1 g of succinic acid and 49 parts of 1,4-butanediol. 0.6 g, 5.0 g of 90% L-lactic acid aqueous solution,
180 μl of tetrabutoxy germanium was charged. Nitrogen gas was introduced into the contents of the container with stirring, the temperature was raised to 185 ° C. under a nitrogen gas atmosphere, and the reaction was carried out at this temperature for 50 minutes, and then under a reduced pressure of 20 mmHg for 1.8 hours.
Subsequently, the temperature was set to 220 ° C., and polymerization was carried out for 2 hours under a reduced pressure of 0.5 mmHg. ^{1 of the} obtained polyester
The polymer composition by H-NMR was 4.4 mol% lactic acid unit, 47.8 mol% 1,4-butanediol unit, 47.8 mol% succinic acid unit, Mn was 69,000, and tensile properties were measured. Was as shown in Table-1. Further, the same biodegradability as in Example 1 was recognized.

[Embodiment 3] 118.1 g of succinic acid and 99 of 1,4-butanediol are placed in a reaction vessel having a capacity of 300 ml equipped with a stirrer, a nitrogen inlet tube, a heating device, a thermometer, and an auxiliary agent addition port. 1 g, germanium oxide 1
Then, 6.3 g of a 90% aqueous lactic acid solution dissolved by weight% was charged. Nitrogen gas was introduced into the contents of the container with stirring, the temperature was raised to 185 ° C. under a nitrogen gas atmosphere, the reaction was carried out at this temperature for 0.5 hours, and then the internal temperature was raised to 220 ° C. ．
The reaction was carried out for 5 hours. Subsequently, polymerization was carried out for 4 hours under a reduced pressure of 0.5 mmHg. ^{1 of the} obtained polyester
The polymer composition by H-NMR is 3.0 mol% of lactic acid unit, 48.5 mol% of 1,4-butanediol unit, 48.5 mol% of succinic acid unit, Mn of 62,500, and tensile properties. Was as shown in Table-1. Further, the same biodegradability as in Example 1 was recognized.

[Example 4] 118.1 g of succinic acid, 99.1 g of 1,4-butanediol and 1% by weight of germanium oxide were dissolved in the same reaction vessel used in Example 3 in advance. % Glycolic acid aqueous solution 6.3 g
Was charged. While stirring the contents of the container, introducing nitrogen gas,
The temperature was raised to 185 ° C. under a nitrogen gas atmosphere, and at this temperature 0.5
After reacting for a time, the internal temperature was raised to 220 ° C. and the reaction was carried out at this temperature for 0.5 hours. Subsequently, polymerization was carried out for 6 hours under a reduced pressure of 0.5 mmHg. The polymer composition by ¹ H-NMR of the obtained polyester was 2.4 mol% of glycolic acid units and 4 of 1,4-butanediol units.
8.8 mol%, succinic acid unit 48.8 mol%, M
n was 42,500. Further, the same biodegradability as in Example 1 was recognized.

[Embodiment 5] 100.3 g of succinic acid and 21.
9 g, 103.1 g of 1,4-butanediol, and 6.3 g of a 90% lactic acid aqueous solution in which 1% by weight of germanium oxide was dissolved in advance were charged. While stirring the contents of the container, nitrogen gas was introduced, and the temperature was raised to 185 ° C. in a nitrogen gas atmosphere.
After reacting for 0.5 hour, the temperature was raised to 220 ° C. and the reaction was performed for 0.5 hour. Subsequently, polymerization was carried out for 4 hours under a reduced pressure of 0.5 mmHg. M of the obtained polyester
n was 71,000, the melting point was 95 ° C., and the tensile properties were as shown in Table 1. The polymer composition by ¹ H-NMR was lactic acid unit 2.8 mol%, 1,4-butanediol unit 48.9 mol%, succinic acid unit 40.8 mol%, and adipic acid unit 7.5 mol%. As a result of the biodegradability test, the film after 3 months was broken, and biodegradability was confirmed.

Comparative Example 1 59.1 g of succinic acid, 47.3 g of 1,4-butanediol and 0.05 g of germanium oxide were placed in the same reaction vessel used in Example 2. Nitrogen gas was introduced into the contents of the container with stirring, the temperature was raised to 185 ° C. in a nitrogen gas atmosphere, and the reaction was carried out at this temperature for 50 minutes, and then under a reduced pressure of 20 mmHg for 2 hours. Subsequently, the temperature was set to 220 ° C. and polymerization was carried out for 4 hours under a reduced pressure of 0.5 mmHg. The Mn of the obtained polyester was 1,500, and the tensile properties were as shown in Table 1.

[Comparative Example 2] 118.0 g of succinic acid and 99.99% of 1,4-butanediol were placed in a reaction vessel having a capacity of 300 ml equipped with a stirrer, a nitrogen inlet tube, a heating device, a thermometer, and an auxiliary agent addition port. 1 g and 6.3 g of a 90% lactic acid aqueous solution in which 1% by weight of antimony oxide was previously dissolved were charged. Nitrogen gas was introduced with stirring the contents of the container, the temperature was raised to 185 ° C. under a nitrogen gas atmosphere, and the reaction was conducted for 0.5 hour.
The temperature was raised to 0 ° C. and the reaction was performed for 0.5 hours. 0.5m continuously
Polymerization was carried out for 4 hours under reduced pressure of mHg. The Mn of the obtained polyester was 8,800. Again ¹
The polymer composition by H-NMR was lactic acid unit 2.9 mol%, 1,4-butanediol unit 48.7 mol%, and succinic acid unit 48.4 mol%.

[0036]

[Table 1]

From the results of the above Examples and Comparative Examples, the following is clear. (1) The polyester copolymer having an aliphatic oxycarboxylic acid unit according to the present invention has a high molecular weight (see Example 1
~ Example 5), high tensile properties are exhibited (Examples 2 to 3). (2) On the other hand, the polyester copolymer of Comparative Example,
Low molecular weight and insufficient tensile properties (Comparative Example 1)
~ Comparative Example 2).

Example 6 100.1 g of succinic anhydride and 1,4-butanediol were placed in a reaction vessel having a capacity of 300 ml equipped with a stirrer, a nitrogen inlet tube, a heating device, a thermometer, and an auxiliary agent addition port. 99.1 g, 6.3 g of a 90% lactic acid aqueous solution in which 1% by weight of germanium oxide was dissolved in advance (6.3 mol% based on the number of moles of succinic anhydride) were charged, and the content was 0.5 at 185 ° C. in a nitrogen atmosphere. After reacting for 22 hours,
The temperature was raised to 0 ° C. and the reaction was performed for 0.5 hours. 0.5 continuously
Polymerization was performed for 6 hours under reduced pressure of mmHg.

The polyester obtained is white and has a Mn
Was 67,600. The melting point was 108 ° C. The polymer composition by ¹ H-NMR was 3.2 mol% for lactic acid units, 48.4 mol% for succinic acid units, and 1,4-
The butanediol unit was 48.4 mol%. The polyester obtained is hot pressed on a tabletop at 200 ° C. and 100 kg / cm ^2.
When a film having a thickness of 0.35 mm was prepared with, a tough film was obtained. Regarding the tensile strength, the breaking strength was 320 kg / cm ² and the elongation was 330%. As a result of the biodegradability test, a large number of worm-eaten holes were observed on the film after 3 months and biodegradability was confirmed.

[Embodiment 7] 100.1 g of succinic anhydride and 1,4-butanediol were placed in a reaction vessel having a capacity of 300 ml equipped with a stirrer, a nitrogen inlet tube, a heating device, a thermometer, and an auxiliary agent addition port. 99.1 g, 90% lactic acid aqueous solution 10.6
g (10.6 mol% with respect to the number of moles of succinic anhydride) and 0.2 g of tetrabutoxy germanium,
After reacting at 185 ° C for 0.5 hours in a nitrogen atmosphere, 2
The temperature was raised to 20 ° C. and the reaction was performed for 0.5 hours. Then 0.
Polymerization was carried out for 5 hours under a reduced pressure of 5 mmHg.

The polyester obtained was white and had a Mn of 7
It was 10,000. The melting point was 103 ° C.
The polymer composition by ¹ H-NMR is 4.
The content was 9 mol%, the succinic acid unit was 47.6 mol%, and the 1,4-butanediol unit was 47.5 mol%. A film having a thickness of 0.35 mm was prepared from the obtained polyester by hot pressing on a table, and a tough film was obtained. Its tensile strength was a breaking strength of 470 kg / cm ² , and an elongation of 630%.
Met. Further, the same biodegradability as in Example 6 was recognized.

[Embodiment 8] 50.1 g of succinic anhydride and 5 succinic acid were placed in a reaction vessel having a capacity of 300 ml equipped with a stirrer, a nitrogen inlet tube, a heating device, a thermometer, and an auxiliary agent addition port.
9.1 g, 1,4-butanediol 99.1 g, and germanium oxide 1% by weight dissolved in 1% by weight of 70% glycolic acid aqueous solution 6.3 g (11 mol% based on the total number of moles of succinic anhydride and succinic acid). ) Was charged and reacted at 185 ° C. in a nitrogen atmosphere for 0.5 hour, then 220 ° C.
The temperature was raised to 0 and the reaction was carried out for 0.5 hours. 0.5 continuously
Polymerization was performed for 5 hours under reduced pressure of mmHg.

The polyester obtained was white and had a Mn of 6
It was 10,000. Further, the polymer composition by ¹ H-NMR was as follows: glycolic acid unit 5.0 mol%, succinic acid unit 47.5 mol%, 1,4-butanediol unit 47.5.
It was mol%. When a film having a thickness of 0.35 mm was prepared from the obtained polyester by hot pressing on a table, a tough film was obtained, and its tensile strength was 300 at break strength.
The kg / cm ² and the elongation were 310%. Further, the same biodegradability as in Example 6 was recognized.

Comparative Example 3 100.1 g of succinic anhydride and 1,4-butanediol were placed in a reaction vessel having a capacity of 300 ml equipped with a stirrer, a nitrogen inlet tube, a heating device, a thermometer, and an auxiliary agent addition port. Was charged with 99.1 g of 185 in a nitrogen atmosphere.
After reacting at 0 ° C for 0.5 hours, the temperature is raised to 220 ° C,
Reacted for 0.5 minutes. Subsequently, 0.06 g of tetrabutyl titanate was added, and polymerization was carried out for 4 hours under a reduced pressure of 0.5 mmHg. The polyester obtained was in the form of an off-white wax and had an Mn of 7,500. An attempt was made to make a film from the obtained polyester by hot pressing on a table, but the film was brittle and could not be obtained.

Comparative Example 4 The number average molecular weight is 65,100.
A 35 mm thick film of aliphatic polyester (Bionore # 1010, manufactured by Showa High Polymer Co., Ltd.) containing 1,4-butanediol units and succinic acid units containing a small amount of urethane bond was prepared with a tabletop hot press and stretched. The test showed that the breaking strength was 330 kg / cm ² and the elongation was 280.
%Met.

[Comparative Example 5] In a reaction vessel having a capacity of 200 ml equipped with a stirrer, a nitrogen inlet tube, a heating device, a thermometer, and an auxiliary agent addition port, 103.5 g of 90% L-lactic acid aqueous solution and germanium oxide. Charge 05g, 1 in a nitrogen atmosphere
The mixture was stirred at 80 ° C. for 2 hours at normal pressure, then depressurized to 20 mmHg over 1 hour, and reacted for 2 hours. Subsequently, the temperature was raised over 1 hour, and a polycondensation reaction was performed for 8 hours under the conditions of 200 ° C. and 2 mmHg. The obtained polylactic acid was slightly yellowish but transparent, and had Mn of 28,000.
Met. An attempt was made to make a film from the obtained polyester by hot pressing on a table, but the film was brittle and could not be obtained.

[0047]

INDUSTRIAL APPLICABILITY The present invention has the following special advantageous effects and its industrial utility value is extremely large. 1. The aliphatic polyester copolymer according to the present invention has a practically sufficient high molecular weight and can be molded into a target molded article by a general-purpose plastic molding method, and the obtained film, molded article, fiber or the like molded article. Has excellent thermal stability and excellent physical properties such as tensile strength. 2. The aliphatic polyester copolymer according to the present invention has excellent biodegradability.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takayuki Ota 1000 Kamoshida-cho, Aoba-ku, Yokohama, Kanagawa Mitsubishi Chemical Corporation Yokohama Research Institute (72) Inventor Hiroaki Yamaoka 1000 Kamoshida-cho, Aoba-ku, Yokohama, Kanagawa Mitsubishi Chemical Co., Ltd. Yokohama Research Institute

Claims (7)

[Claims] 1. An aliphatic oxycarboxylic acid unit represented by the following formula (I): 0.02 to 30 mol%, and an aliphatic or alicyclic diol unit represented by the following formula (II): 35 to 49.9.
An aliphatic polyester comprising 9 mol% and 35 to 49.99 mol% of an aliphatic dicarboxylic acid unit represented by the following formula (III), and having a number average molecular weight of 10,000 to 200,000. Copolymer. ^{(I) -O-R 1 -CO-} ( wherein, R ¹ represents a divalent aliphatic hydrocarbon group) in ^{(II) -O-R 2 -O-} ( wherein, R ² is a divalent aliphatic hydrocarbon group or a divalent alicyclic hydrocarbon group) (III) in -OC-R ³ -CO- (wherein, R ³ is a direct bond or a divalent aliphatic hydrocarbon group) 2. —R ² — in the formula (II) is — (CH
₂ ) An aliphatic hydrocarbon group represented by _n- (n is an integer of 2 to 10) or a divalent alicyclic hydrocarbon group having 3 to 10 carbon atoms, and -R ^{3 in the} formula (III). -Is-(CH
₂ ) _m- (m is 0 or an integer of 1-10), The aliphatic polyester copolymer according to claim 1. 3. The aliphatic polyester copolymer according to claim 1, wherein the formula (I) is an aliphatic oxycarboxylic acid unit represented by the following formula (IV). Embedded image (In the formula, l is 0 or an integer of 1 to 10) 4. A formula (I) is a lactic acid unit or a glycolic acid unit, a formula (II) is a 1,4-butanediol unit, and (III).
Aliphatic polyester copolymer according to any one of claims 1 to 3, characterized in that the formula is a succinic acid unit. 5. When producing an aliphatic polyester having a number average molecular weight of 10,000 to 200,000 by reacting an aliphatic or alicyclic diol and an aliphatic dicarboxylic acid or a derivative thereof by a polycondensation reaction in the presence of a catalyst. , Aliphatic oxycarboxylic acid to aliphatic dicarboxylic acid or derivative thereof 10
The method for producing an aliphatic polyester copolymer according to any one of claims 1 to 4, wherein 0.04 to 60 mol of copolymerization is carried out with respect to 0 mol. 6. The method for producing an aliphatic polyester copolymer according to claim 5, wherein the catalyst is a germanium compound. 7. A method of dissolving germanium oxide in an aqueous solution of an aliphatic oxycarboxylic acid, adding this to an aliphatic or alicyclic diol and an aliphatic dicarboxylic acid or a derivative thereof, and performing polycondensation. 5 or the method for producing the aliphatic polyester copolymer according to claim 6.